Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Virtual colonoscopy is a technique that uses a
computerized tomographic (CT)
scan (a type of three-dimensional x-ray) to construct virtual images of the
colon that are similar to the views of the colon obtained by direct observation
by optical colonoscopy.
In preparation for virtual colonoscopy, the day before the examination the
colon is emptied using laxatives in a manner similar to optical colonoscopy.
During the examination, a small tube is inserted into the anus to inject and
fill the colon with air. Unlike with optical colonoscopy, this tube is not
advanced into the colon. The CT scan then is performed, and the scans are
manipulated by computer software to form virtual images of the colon. When
properly performed, virtual colonoscopy can be as effective as optical
colonoscopy. It can even find polyps "hiding" behind folds that occasionally are
missed by optical colonoscopy. The scanning takes only 10 minutes, and usually
no conscious sedation is necessary.
In October, 2007, researchers from University of Wisconsin published in the
New England Journal of Medicine a study comparing traditional optical
colonoscopy to virtual colonoscopy. More than six thousand patients over age 50
were evenly divided to undergo either optical or virtual colonoscopy. The
researchers found that virtual colonoscopy was as effective as optical
colonoscopy in detecting polyps larger than 5mm.
Comparing virtual colonoscopy and optical colonoscopy
Virtual colonoscopy is less invasive and faster to perform than optical
colonoscopy and does not require conscious sedation.
Even though virtual colonoscopy is less invasive than optical colonoscopy,
virtual colonoscopy still involves injecting air into the colon, which can be
uncomfortable for some patients. On the other hand, with adequate conscious
sedation, patients usually experience little or no discomfort with optical
colonoscopy.
Virtual colonoscopy is not as reliable as optical colonoscopy in detecting
small polyps (less than 5mm in size). Even though most experts believe that
polyps smaller than 5mm are usually benign, some small polyps can be cancerous
or become cancerous if not removed.
Virtual colonoscopy is not as accurate as colonoscopy in finding flat
cancers or polyps that are not protruding, that is, are not polyp-like.
Virtual colonoscopy cannot remove polyps. If polyps are found by virtual
colonoscopy, then optical colonoscopy must be performed to remove the polyps.
Therefore, many individuals having virtual colonoscopy will have to undergo a
second procedure, optical colonoscopy.
Even though the amount of radiation exposure with virtual colonoscopy is
considered safe, the long term radiation effects of mass screening with CT is
not known.
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
Rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Rectal bleeding may be moderate to severe and most bleeding comes from the colon, rectum, or anus. Common causes include anal fissures, hemorrhoids, diverticulitis, and more.
Colon cancer is a malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from colonic polyps. Removal of these precancerous polyps can prevent colon cancer.
A colon polyp is a benign tumor of the large intestine. Benign polyps do not invade nearby tissue or spread to other parts of the body. Benign polyps can easily be removed during colonoscopy and are not life threatening. If benign polyps are not removed from the large intestine, they can become malignant over time.
Disease prevention in men includes routine screening tests that are part of basic prevention medicine. Take an active role in your own health care and discuss screening tests with your doctor early in life. Age of screening and timing of screening depends upon the condition being assessed.
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